The derecho storm potentially affected some 10 million acres of Iowa farmland and millions of bushels of grain storage in the top U.S. corn-growing state, Iowa Agriculture Secretary Mike Naig said.

Early estimates show that tens of millions of bushels worth of commercial grain storage — as well as millions of bushels of on-farm storage bins owned by producers — were either affected, destroyed or severely damaged by the storm last week, Naig said.

Bin losses, ahead of this fall’s harvest, could leave some farmers scrambling to find storage for their crops.

How much of the downed corn will be able to produce a viable crop this fall is unknown, and it is too early to put a total value on the damage to the crop and the state’s overall agricultural sector, Naig said.

But it is too late for farmers to try to replant, agronomists said, given that harvest typically begins in either September or October.

The storm packing hurricane-force winds tore across the U.S. Midwest on Monday, causing widespread property damage in cities and rural towns. More than 1 million U.S. homes and businesses remained without power into the middle of the week.

Corn is a staple of Iowa’s agricultural economy. The state produced about 2.58 billion bushels of corn in 2019 — or about 19% of all corn grown in the United States, according to U.S. Department of Agriculture data.

This year, USDA reported that Iowa farmers planted 14 million corn acres — or more than half of all the farmland in the state growing grains, oilseeds and other crops.

Chicago corn prices surged to the highest level in nearly three weeks on Thursday as worries over storm damage in the U.S. Midwest countered pressure from huge government harvest forecasts.

The USDA on Wednesday said U.S. farmers would reap a record corn harvest and a second-biggest soybean crop, buoyed by favorable weather.

However, selling pressure was limited as the market assessed the impact of the derecho storm, which came after the Aug. 1 cutoff point for crop conditions used by the USDA for its August forecasts.